I believe there is good research that shows a genetic propensity for addiction. But even if you inherit a particular gene it might not express itself for various reasons. I'm sure there's a strong streak in my family. My parents both had problems with drinking inappropriately at certain times in their lives. Of 4 sisters, 1 was a full-blown alcoholic and this had horrible consequences for her family, 1 has no problem, 1 (me) is an alcoholic who caught it relatively early, and 1 just loves drinking but is determined not to allow herself to slide into excessive consumption.